Where do fine particles come from?

Every year in France, air pollution and fine particles cause 40,000 premature deaths. If we’re going to reduce that impact, we need to understand more about them. But behind the generic term “fine particles” lurks a variety of meanings. Fine particles can take different sizes and shapes, can be made up of different things, and can come from different sources. It’s time to take a closer look.

Natural and human-made sources

  • Some fine particles come from natural sources and are difficult to prevent. They might be emitted during volcanic eruptions, desert sandstorms, forest fires or earthquakes. They can also be produced in sea spray and wind-eroded soil. Volatile organic compounds sometimes come from certain plant species and form fine particles in a chemical reaction with the air.


  • But most fine particles are generated by humans. The top two sources are home heating in residential areas (wood-burning fires especially) and road transport. These activities are therefore respectively responsible for half and a quarter of fine particle emissions in Ile-de-France. Industry, construction,agriculture, forestry (spreading, tillage) and non-road transport also actively contribute to fine particle air pollution.

Primary particles, secondary particles and resuspended particles

Combustion, friction, chemical reactions: fine particles are generated for a variety of reasons.

  • They can be emitted directly into the atmosphere due to combustion or friction, when a material is gradually broken down. These are known as “primary particles”. Primary particles are generated by forms of transport, home heating systems, and industrial or agricultural activities. In the case of petrol or diesel vehicles, fine particles come both from the exhaust gases produced by fuel combustion and from abrasion – friction – between brakes and tyres.
  • But fine particles can also be created as a result of chemical reactions with atmospheric gases such as sulphur dioxide (SO2), nitrogen oxides (NOx) and volatile organic compounds (VOCs), known collectively as “secondary particles”.
  • Once they have fallen to the ground, these fine particles have not yet finished their journey. They can be resuspended in the atmosphere. For example, fine particles on roads are lifted into the air again when a car passes.


Even though fine particles originate from various sources and phenomena, they are all dangerous to health and disruptive to ecosystems. Underestimated by lawmakers, this invisible threat nevertheless generates far too many medical issues and exposes local residents to dangerous and sometimes fatal diseases. A connection has been found with a number of respiratory (pharyngitis, tracheitis, bronchitis, asthma, etc.), cardiovascular (arrhythmia, heart attacks, thrombosis, etc.), and neurodegenerative diseases (Alzheimer’s, Parkinson’s) and an increased risk of cancer (particularly of the lungs). It is high time to eliminate out this evil.

Discover more questions

Electric vehicles help fight against global warming and reduce the air pollution that causes 307,000 premature deaths in Europe every year. But electric vehicles are not a miracle solution. They require a lot of energy to produce, charging them may need large amounts of fossil fuels (depending on the source of the electricity used) and – like petrol or diesel cars – they emit fine friction particles.
Stinging eyes, breathlessness, a cough that won’t budge: air pollution – especially when it’s cause by fine particles – is irritating, but can also be the cause of serious diseases. It even puts lives in danger: in France, air pollution cuts life expectancy by two years. And in New Delhi, this figure leaps to 10 years. In terms of deaths on a global scale, air pollution is just as dangerous as smoking, and even more serious than alcohol and unclean water (there are three times as many air pollution-related deaths) and HIV (six times more). Who is most at risk? People suffering from respiratory and cardiac disorders, diabetes, infants, seniors and pregnant women.
One in five deaths around the world is attributable to outdoor air pollution yet politicians are struggling to remedy the situation. In France, the government has even been found at fault by the Court of Justice of the European Union and the French Council of State for not doing enough, while air pollution causes more than 40,000 premature deaths every year. What’s to blame? Natural phenomena certainly contribute (pollen, forest fires, soil erosion, volcanic eruptions, etc.), but most of the damage is caused by human activity (agriculture, industry, transport, construction, etc.), which generates gases and fine particles. In some parts of France transport is the worst culprit, in others, agriculture comes top of the list. In the fight against outdoor air pollution in France, measures must now be taken on domestic heating and road transport, which are respectively responsible for half and a quarter of fine particle emissions in Ile-de-France.